OSI Model Advantages and Basic Purpose Explained

A networking model defines the process by which information is transferred between networking components. Similar to a blueprint that specifies the materials and technologies for constructing a house, a networking model outlines the protocols and devices required to establish a network.

A networking model consists of a comprehensive set of documents that specify the procedures and standards for network operations. Each document addresses a specific functionality, protocol, or device relevant to a particular segment of the network.

The OSI Model

During the initial development of computer networking, vendors developed proprietary networking models tailored to their own products. These models restricted communication to devices produced by the same manufacturer. For instance, IBM computers could only communicate with other IBM devices.

This arrangement was disadvantageous for both manufacturers and consumers. Manufacturers were compelled to produce all necessary networking devices, while consumers were required to purchase all components from a single vendor.

To address these limitations, leading hardware manufacturers agreed to adopt or support a vendor-neutral networking model alongside their proprietary models. Two significant initiatives were undertaken to develop such a model. The first initiative was led by the International Organization for Standardization (ISO), which developed the Open Systems Interconnection (OSI) model. The second was undertaken by the U.S. Department of Defense (DoD), resulting in the creation of the TCP/IP model.

Objectives of the OSI Model

The OSI model was developed to achieve the following objectives.

• To standardize data networking protocols, enabling communication among all networking devices globally.
• To establish a common platform for software developers and hardware manufacturers, facilitating the development of interoperable networking products.
• To assist network administrators by segmenting the data exchange process into smaller, more manageable components, thereby simplifying understanding, management, and troubleshooting.

The Layered Approach

A layered approach is a hierarchical way to address all required technologies and devices in communication. It allows vendors and manufacturers to build and design specific applications and hardware into one layer for a particular purpose without affecting the entire network protocol stack.

The OSI model employs a layered approach, dividing the communication process into seven distinct layers. Each layer specifies a particular functionality, along with the protocols and devices required to implement it.

Advantages of the OSI Model

The advantages of the OSI Model are the following.

• Assists network administrators in identifying the necessary hardware and software for network construction.
• Encourages hardware manufacturers to develop networking products that can interoperate within a network.
• Serves as an educational tool for understanding the communication processes between networking components.
• Divides complex networking functions into simpler, more manageable components.
• Make troubleshooting easier by allowing network administrators to identify the issue at the layer causing it rather than searching the entire network.

Disadvantages of the OSI Model

• It defines various services multiple times. For example, the error control service is defined in both Transport and Data Link layers.
• The model does not permit parallel operation of layers; each layer must wait to receive data from the preceding layer.
• Instead of defining similar functions in the same layer, it defines them in different layers, which adds additional complexity.
• Instead of providing a summary of rarely used protocols and functions, it defines every protocol and function in detail, making the model lengthy and less useful for administrators.

The OSI Model in Contemporary Networks

Modern computer networks do not use the OSI model. They use the TCP/IP model. Despite this, almost all popular networking courses include the OSI model. There are two main reasons behind this. First, during the years when many people believed the OSI model would become commonplace in networking, vendors, administrators, networking courses, and documents began using the OSI model terminology. That terminology remains today. Second, the OSI model describes every concept, function, and protocol in detail. Once you learn this model, you can easily learn the TCP/IP model by learning the difference between the two models.

Conclusion

The OSI model remains a foundational concept in networking, providing a universal framework for understanding and designing network systems. While it is no longer implemented in modern networks, its layered approach and comprehensive terminology continue to influence network education and the development of interoperable technologies. By mastering the OSI model, you can gain valuable insights that make it easier to understand and troubleshoot complex network architectures and adapt to evolving technologies such as the TCP/IP model.